Full Idea
When one attends to something existing in space, one attends to an instance of redness, not to redness itself (which is a colour, which resembles orange). The facts about red itself are not spatial facts, but are traditionally seen as a priori synthetic.
Gist of Idea
There are spatial facts about red particulars, but not about redness itself
Source
J.P. Moreland (Universals [2001], Ch.4)
Book Reference
Moreland,J.P.: 'Universals' [Acumen 2001], p.90
A Reaction
This is the fact that properties can themselves have properties (and so on?), which seems to take us further and further from the natural world.